U.S. orders 15 Cuban diplomats to leave

In this Sept. 29, 2017 photo, a worker carries cardboard inside the compound of the United States embassy in Havana, Cuba, Friday, Sept. 29, 2017. The United States expelled 15 of Cuba's diplomats Tuesday to ... more

In this Sept. 29, 2017 photo, a worker carries cardboard inside the compound of the United States embassy in Havana, Cuba, Friday, Sept. 29, 2017. The United States expelled 15 of Cuba's diplomats Tuesday to protest its failure to protect Americans from unexplained attacks in Havana, plunging diplomatic ties between the countries to levels unseen in years. (AP Photo/Desmond Boylan) less

Photo: Desmond Boylan, STR

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Maritza Martinez waits for customers at her home where she rents a room in Havana, Cuba, Tuesday, Oct. 3, 2017. Thousands of private Cuban businesses have invested heavily in private homes, cars and ... more

Maritza Martinez waits for customers at her home where she rents a room in Havana, Cuba, Tuesday, Oct. 3, 2017. Thousands of private Cuban businesses have invested heavily in private homes, cars and restaurants, hoping to cash in on an expected wave of American travelers to the island. Now that the U.S. State Department has issued a travel warning for the country, their investments are at risk.(AP Photo/Desmond Boylan) less

Photo: Desmond Boylan, STR

WASHINGTON - The United States expelled 15 of Cuba's diplomats Tuesday to protest its failure to protect Americans from unexplained attacks in Havana, plunging diplomatic ties between the countries to levels unseen in years.

Only days ago, the U.S. and Cuba maintained dozens of diplomats in newly re-opened embassies in Havana and Washington, powerful symbols of a warming relationship between longtime foes. Now both countries are poised to cut their embassies by more than half, as invisible, unexplained attacks threaten delicate ties between the Cold War rivals.

Given one week to leave

The State Department gave Cuba's ambassador a list Tuesday of 15 names and ordered them out within one week, officials said, in a move that aims to "ensure equity" between each nation's embassy staffing. Last week, the U.S. announced it was withdrawing 60 percent of its own diplomats from Havana because they might be harmed if they stay.

The dual moves marked a sharp escalation in the U.S. response to attacks that began nearly a year ago and yet remain unexplained despite harming at least 22 Americans - including a new victim identified this week.

Still, U.S. officials emphasized they were not accusing Cuba of either culpability or complicity, merely a failure to stop whatever is happening to Americans working out of the U.S. Embassy.

Havana blasts order

Investigators have explored the possibility of a "sonic attack" harming diplomats through sound waves, but have discovered no device and identified no culprit.

"We continue to maintain diplomatic relations with Cuba, and will continue to cooperate with Cuba as we pursue the investigation into these attacks," said Secretary of State Rex Tillerson.

Havana blasted the U.S. order, calling it "irresponsible" and "hasty." In the Cuban capital, Foreign Minister Bruno Rodriguez called a news conference to again deny involvement and defend his country's efforts to assist in the U.S. investigation.

The scope of the attacks has continued to grow. The U.S. disclosed Tuesday that the 22nd victim was confirmed the day before. In recent weeks the State Department had said there were 21 individuals "medically confirmed" to be affected by attacks that harmed their hearing, cognition, balance and vision, some with diagnoses as serious as brain injury.